Preservatives are employed in various non-limiting industrial applications including personal care, household, coatings, metalworking fluids, paper, wood, plastics, disinfection, cosmetics, toiletry, pharmaceuticals, food, beverages, oral care, paints, and water treatment to prevent microbial contamination, of which, the personal care products engage significant amount of preservatives. It is mandatory on the part of formulators to give due consideration for product safety and environmental impact of the ingredients of the composition that they develop.
The prior art discloses use of a variety of glycols for preparing preservative or antimicrobial compositions. Sometimes glycols per se are used as a preservative component. In many laboratories ethylene glycol has replaced formaldehyde to preserve organisms. However, the use of ethylene glycol is limited in food and personal care industries due its toxicity. So, there is a necessity to replace ethylene glycol with a solvent which is non toxic. The limitation of ethyleneglycol is partly addressed by chemically synthesized propylene glycol which has been widely used in many applications such as food, cosmetics, personal care, bakery, etc. Such compositions comprising chemically synthesized propylene diols were found to have an irritation potential, and harmful and toxic impurities produced from the chemical processes used to synthesize it.
Further, the use of diols, glycols and alcohols for preserving cosmetic, dermatological or pharmaceutical, personal care, household, disinfection, toiletry, food, beverage, and oral care compositions is limited by statutory regulatory instruments. Countries often have maximum concentration ranges to be employed in their respective approved regulated products. Additionally, an unwanted lowering of viscosity is observed with usage of higher percentage of solvents like alcohols in the end-user applications, thus, there is a limitation to employ higher concentration levels of alcohols.
To protect end-users against the microbial attack and from the side effects of excessive use levels of antimicrobial active ingredients, it is beneficial to have reduced concentration levels of Tropolone, an antimicrobial active of the present application. In this regard, mild and harmless efficacy enhancers of Tropolone could render the opportunity of decreasing the use concentration levels of Tropolone, an antimicrobial agent.
US Publication No. 20110086918 discloses a composition having effective broad spectrum preservation activity comprising benzyl alcohol, salicylic acid, sorbic acid, and a compound selected from the group consisting of 1,3-propanediol, glycerin and combinations thereof.
US Publication No. 20080176957 discloses a preservative compositions comprising 1,3-propanediol, wherein the 1,3-propanediol in said composition has a bio-based carbon content of about 1% to 100%. In addition, it is preferred that the 1,3-propanediol be biologically-derived, and wherein upon biodegradation, the biologically-derived 1,3-propanediol contributes no anthropogenic CO2 emissions to the atmosphere.
US Publication No. 20120100085 discloses liquid compositions which contain (a) from 5 to 95% by wt of sorbitan monocaprylate and (b) from 5 to 95% by weight of one or more alcohols of formula (1) R—OH, and wherein the liquid compositions are suitable for the production of cosmetic, dermatological or pharmaceutical products.
US Publication No. 20090306154 discloses an antimicrobial mixture comprising or consisting of: (a) one, two or more tropolone derivatives; (b) one or more compounds selected from the group consisting of: chlorphenesin, imidazolidinyl urea, DMDM hydantoin, ethylhexylglycerin, diazolidinyl urea, sodium hydroxymethylglycinate and polyaminopropyl biguanide or salts or solvates thereof; and (c) one or more additional constituents selected from the group consisting of: methylchloroisothiazolinone, methylisothiazolinone, chlorohexidine, benzethonium chloride, 2-bromo-2-nitropropane-1,3-diol, methylpropanediol, dimethyl phenylpropanol and 4-methyl-4-phenyl-2-pentanol or salts or solvates thereof.
US Publication No. 20070265352 discloses an antimicrobial composition, comprising an antimicrobial effective amount of (a) at least one straight-chain 1,2-alkanediol, the chain length of which is in the range of 5 to 10 C-atoms, and (b) at least one preservative selected from sorbate and its salts, parabenes, iodopropynyl butylcarbamate, ethylene diamene tetraacetic acid and its salts, tropolone compounds and sisquiterpenes. Component (a) comprises: 1,2-hexanediol and 1,2-octanediol, 1,2-hexanediol and 1,2-decanediol, 1,2-pentanediol, 1,2-hexanediol and 1,2-octanediol, 1,2-hexanediol, 1,2-octanediol and 1,2-decanediol or 1,2-pentanediol, 1,2-hexanediol and 1,2-decanediol, the proportions of the said diols in the mixture being set such that their antimicrobial action is synergistically intensified.
US Publication No. 20070059331 discloses an antimicrobial mixtures comprising or consisting of one or more branched or unbranched alkanediols having 6-12 carbon atoms, one, two or more compounds chosen from the group consisting of the tropolones, wherein 1,2-hexanediol, 1,2-octanediol or 1,2-decanediol or a mixture of 1,2-hexanediol and 1,2-octanediol or a mixture of 1,2-hexanediol and 1,2-decanediol or a mixture of 1,2-octanediol and 1,2-decanediol or a mixture of 1,2-hexanediol, 1,2-octanediol and 1,2-decanediol is employed as constituent branched or unbranched alkanediols.
US Publication No. 20070054967 discloses antimicrobial active compounds, and in particular certain mixtures, formulations and foodstuffs comprising certain compounds (alcohols, ethers, esters, acids, corresponding salts and solvates) of a formula (I) and at least one tropolone (derivative) of the formula (II) and to products comprising such mixtures in an antimicrobially active amount.
US Publication No. 20120101135 discloses liquid compositions which contain (a) from 40 to 99.9% by wt of sorbitan monocaprylate and (b) from 0.1 to 60% by wt of one or more antimicrobial substances selected from the group consisting of the components (b1) to (b5): (b1) specific organic acids and the salts thereof, (b2) specific formaldehyde donors, (b3) specific isothiazolinones, (b4) specific paraben esters and the salts thereof, and (b5) specific pyridones and the salts thereof. The liquid compositions are suitable for the production of cosmetic, dermatological or pharmaceutical products.
The antimicrobial activity of tropolone and tropolone derivatives are known from the prior art, e.g., Antimicrob. Agents Chemother. vol. 7(5), 500-506 (1975). However, the studies of synergistically intensified activity against antibacterial and antifungal strains of a combination of (i) Tropolone with (a) 1,3-propanediol and/or (b) sorbitan caprylate, bio-derived solvents is not disclosed in any prior art.
In view of foregoing, there remains a need for an eco-friendly, non-aqueous and stable antimicrobial solution composition comprising a solvent which is free from toxins, non-irritant for the skin, and preferably acceptable by various regulatory authorities around the globe.
Accordingly, it is a primary objective of the present application to provide an antimicrobial composition which can provide effective antimicrobial activity at lower use levels of the antimicrobial agent in the presence of said solvent or solvent system, i.e., 1,3-propanediol and/or sorbitan caprylate.
Another objective of the present application is to provide an antimicrobial composition comprising lower concentration levels of solvents such as alcohols in order to limit the impact on the viscosity of the end user products.
It is a further objective of the present application to provide an eco-friendly, non-aqueous and stable antimicrobial solution composition comprising (i) tropolone; (ii) 1,3-propanediol; and/or (iii) sorbitan caprylate.